Concurrent removals of certain anonymous shared memory mappings by using the UMTX_SHM_DESTROY sub-request of UMTX_OP_SHM can lead to decreasing the reference count of the object representing the mapping too many times, causing it to be freed too early.
A malicious code exercizing the UMTX_SHM_DESTROY sub-request in parallel can panic the kernel or enable further Use-After-Free attacks, potentially including code execution or Capsicum sandbox escape.
Exploitability
AV:NAC:LPR:NUI:NScope
S:CImpact
C:HI:HA:H10/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HMemory Safety
Other